1. PHOTOSYNTHESIS

2. What is Photosynthesis? A chemical reaction powered by sunlight that uses carbon dioxide (CO 2 ), and water (H 2 O) to produce glucose and oxygen.A chemical reaction powered by sunlight that uses carbon dioxide (CO 2 ), and water (H 2 O) to produce glucose and oxygen. 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 glucose SUN

3. How to read a chemical equation light energy 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Inputs are on the left = reactants Outputs on the right = products (Energy is not considered a reactant so it is written above: in this reaction energy is needed to break the bonds in H 2 O) Why is there a 6 in front of the carbon dioxide, water, and oxygen molecules but not in front of the glucose molecule?

4. How to read a chemical equation 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Chemical equations are like math: the stuff on one side of the arrow (or equal sign) has to be equivalent to the stuff on the other side. The number of atoms of each kind of element on one side has to match the number of atoms on the other side. We call that a balanced equation. How many carbon atoms are on the reactant side? How many oxygen? How many hydrogen? Does that match the product side?

5. Where does the plant get the CO 2 and H 2 O? Water comes from the soil and travels in veins throughout plant including to the leaves, where photosynthesis takes place? CO 2 is one of many gases in the air But how does the CO 2 get into the leaf?

6. Through small pores called stomata or guard cells These guard cells can open and close.

7. 7 Where does photosynthesis take place?

8. 8 Mesophyll Cell of Leaf Cell Wall Nucleus Chloroplast Central Vacuole Photosynthesis occurs in these cells!

9. Chloroplast Organellephotosynthesis Organelle where photosynthesis takes place. Granum Thylakoid Stroma Outer Membrane Inner Membrane Thylakoid stacks are connected together

10. 10 Thylakoid Thylakoid Membrane Thylakoid Space Granum Grana make up the inner membrane

12. 12 How does the chloroplast work?

13. 13 Chloroplasts contain chlorophyll molecules Chlorophyll is a pigment.Chlorophyll is a pigment. It’s located in the thylakoid membranes.It’s located in the thylakoid membranes. Chlorophyll pigments harvest energy from the sun by absorbing certain wavelengths, especially blue and red.Chlorophyll pigments harvest energy from the sun by absorbing certain wavelengths, especially blue and red. Plants are green because the green wavelength is reflected, not absorbedPlants are green because the green wavelength is reflected, not absorbed.

14. 14 Absorption of Light by Chlorophyll wavelength Absorption violet blue green yellow orange red Chlorophyll absorbs blue-violet & red light best

15. So chlorophyll is the molecule that captures the energy from the sun And turns it into energy the plant can use: ATP

16. Plants are autotrophs They take inorganic molecules (CO 2 and H 2 O) and by harvesting the power of the sun, turn them into the organic molecule glucose (C 6 H 12 O 6 ) with O 2 as a byproduct. Without this ability to turn inorganic to organic molecules, life could not exist. So thank a plant today!

17. 17 Energy : from sunlight to ATP Sunlight is the ULTIMATE energy for all life on Earth Plants store energy in the chemical bonds of sugars When those bonds are broken (in our bodies or in the plant) energy is released as ATP.

18. 18 Structure of ATP ATP stands for adenosine triphosphate It is composed of the nitrogen base ADENINE, the pentose (5C) sugar RIBOSE, and three PHOSPHATE groups The LAST phosphate group is bonded with a HIGH ENERGY chemical bond This bond can be BROKEN to release ENERGY for CELLS to use

19. 19 High Energy Phosphate Bond

20. 20 Photosynthesis Has Two Parts

21. 21 Two Parts of Photosynthesis First part: 1.Light Reaction (or Light Dependent Reaction) --Splits water into H+ and O (which is expelled as O 2 ) --Converts energy from sun into chemical energy of ATP and NADPH (another energy carrier molecule). SUN

22. Where does the light reaction take place? In the thylakoid membranes So now we have hydrogen and energy— but not glucose yet

23. 23 Two Parts of Photosynthesis Second part: 2. Calvin Cycle or Light Independent Reaction Uses energy (ATP and NADPH) from light reaction along with the freed hydrogen and the CO 2 to make sugar (glucose).Uses energy (ATP and NADPH) from light reaction along with the freed hydrogen and the CO 2 to make sugar (glucose).

24. 24 Where does the light independent reaction take place? In the stromaIn the stroma Called light independent because this part does not need sunlight to occurCalled light independent because this part does not need sunlight to occur

25. 25 Overall Reaction light energy 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2